title: Solvent-induced helix superstructure in achiral dumbbell-shaped hydrazine derivatives.
abstract: We studied hydrogen-bonding assemblies in a series of dumbbell-shaped hydrazine derivatives, namely oxalyl N',N'-bis(3,4-dialkoxybenzoyl)-hydrazide (BFH-n, n = 4, 6, 8, 10) and oxalyl N',N'-dibenzoyl-hydrazide (FH-0). It has been demonstrated that NH-1 protons of BFH-n precipitated from tetrahydrofuran (THF) or dimethylformamide (DMF) were involved in intramolecular H-bonding to form 6-membered rings. Meanwhile, NH-2 protons of BFH-n precipitated from THF formed intermolecular hydrogen bonds with C═O groups of neighboring molecules, while NH-2 protons of BFH-n precipitated from DMF formed intermolecular hydrogen bonds with C═O group of neighboring DMF molecules. C═O, -CH(3), and -CH groups of DMF molecules participated in multiple intermolecular hydrogen bonds with the -N-H and -C═O groups of FH-0 molecules in single-crystals formed in DMF, leading to a double helix morphology with a pitch of 24.2 Å along the c direction. Both left- and right-handed helical micrometer-length ribbons with nonuniform helical pitches were observed in an achiral BFH-10 xerogel precipitated from DMF.
authors.affiliation: Key Laboratory of Automobile Materials, Ministry of Education, Institute of Materials Science and Engineering, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Xia
authors.initials: X
authors.lastname: Ran
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Songnan
authors.initials: S
authors.lastname: Qu
authors.forename: Haitao
authors.initials: H
authors.lastname: Wang
authors.forename: Binglian
authors.initials: B
authors.lastname: Bai
authors.forename: Huimin
authors.initials: H
authors.lastname: Liu
authors.forename: Chengxiao
authors.initials: C
authors.lastname: Zhao
authors.forename: Min
authors.initials: M
authors.lastname: Li
mesh_terms: D004126:Dimethylformamide / Q000737:chemistry; D005663:Furans / Q000737:chemistry; D006834:Hydrazines / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D008958:Models, Molecular; D008968:Molecular Conformation; D012997:Solvents / Q000737:chemistry*
chemical_list: D005663:Furans; D006834:Hydrazines; D012997:Solvents; C029424:hydrazine; C018674:tetrahydrofuran; D004126:Dimethylformamide